Have we told you this story? We met the McEwans on a train from York, England to London in September 2009, when we were on our home-school launch trip. When we got on the train in York, we discovered that Mary Jo and Andy were sitting in our seats (which were also their seats, as the reservation system had double-booked us). We sat down in empty seats next to them and ended up talking for the entire two-hour journey to London. By the time we arrived in London, we had decided to correspond. When Natalie started sending them issues of her “Applewood Quarterly,” Andy would respond with wonderful letters, which…